Standard dimensions of spectacle blind / 8 blind

A spectacle blind is basically made up of two metal discs attached to each other by a metal strip as shown in the figure. One is solid disc and the other is hollowed. The hollowed disc allows fluid flow and solid disc is used for positive isolation. You can simply rotate a spectacle blind by 180 degrees to close or open a pipe to allow fluid to pass.

Standard dimensions of spectacle blinds or 8 blinds

These standard dimensions of spectacle blinds are in specified in inches. They are as per as per ASME B16.48.